Joint registries suggest a downward trend in the use of uncemented Total Knee Replacements (TKR) since 2003, largely related to reports of early failures of uncemented tibial and patella components. Advancements in uncemented design such as trabecular metal may improve outcomes, but there is a scarcity of high-quality data from randomised trials. 319 patients <75 years of age were randomised to either cemented or uncemented TKR implanted using computer navigation. Patellae were resurfaced in all patients. Patient outcome scores, re-operations and radiographic analysis of radiolucent lines were compared. Two year follow up was available for 287 patients (144 cemented vs 143 uncemented). There was no difference in operative time between groups, 73.7 v 71.1 mins (p= 0.08). There were no statistical differences in outcome scores at 2 years, Oxford knee score 42.5 vs 41.8 (p=0.35), International Knee Society 84.6 vs 84.0 (p=0.76), Forgotten Joint Score 66.7 vs 66.4 (p=0.91). There were two revisions, both for infection one in each group (0.33%). 13 cemented and 8 uncemented knees underwent re-operation, the majority of these being manipulation under anaesthetic (85.7%), with no difference (8.3% vs 5.3%, 95% CI -2.81% to 8.89%, p = 0.31). No difference was found in radiographic analysis at 2 years, 1 lucent line was seen in the cemented group and 3 in the uncemented group (0.67% v 2.09%, 95%CI -4.1% to 1.24%, p = 0.29). We found no difference in clinical or radiographic outcomes between cemented and uncemented TKR including routine patella resurfacing at two years. Early results suggest there is no difference between cemented and uncemented TKR at 2 years with reference to survivorship, patient outcomes and radiological parameters

Introduction. Total knee replacement has been well-established form of treatment both for osteoarthritis and inflammatory arthritis. Both cemented and uncemented TKR have been used successfully. Since 1977 low contact stress (LCS) mobile bearing knee replacement has been in extensive use. Most of the intermediate and long term results reported are in osteoarthritis1–7. Though there are several studies reporting short term performance of TKR in rheumatoid arthritis8–19 there have been rare reports31 of intermediate to long-term performance of LCS uncemented TKR in rheumatoid arthritis. Methods. Retrospective, non-randomised and consecutive study. Case notes and radiological assessment done. Kaplan meyer survival analysis used. Radiological assessment between initial and final xrays done using T test statistics. Assessement done by two independent observer. Results. 108 knees in 67 patients are collected. 21 patients with 36 knees have died. Only 65 knees in 42 patients had both case notes and xrays which are included in this study. Of this 11 knees in 7 patients were dead. All 65 knees in 42 patients are sero-positive rheumatoid arthritis. Pre-operative bone loss was seen only in 4 knees. Bone loss was in the medial side in 3 knees (4,5 and 8mm respectively) and lateral in 1 knee (1 cm). None of these bone loss needed bone grafting or any special procedures. There was no subsidence in any of the 65 knees. Survival of uncemented LCS TKR in inflammatory arthritis patients is 100%. Aseptic failure is 0%. No infective failure. There is no significant change in the implant position. This is the longest follow for uncemented TKR in inflammatory arthritis ever reported in the literature. Conclusion and Discussion. In conclusion, our study has uniformity, as a single surgeon performed/supervised with senior trainees all the operations and all patients received the same level of post-operative care. Survival of LCS uncemented TKR in inflammatory arthritis patients is 100% up to 15years. This is the longest follow up in this patient population ever reported in the literature. Our study shows excellent survival and comparable to other cemented TKRs in this patient population reported in the literature. This study proves contrary to the general belief that uncemented TKR do poor in inflammatory arthritis due to osteoporotic bone

Purpose of study: To determine whether positioning the operated limb in flexion on a CPM machine reduces blood loss following uncemented total knee replacement. We also sought to determine whether limb arterial pressure, represented by ankle-brachial pressure index (ABPI), is affected by position of the limb. Methods: We compared two groups of age and sex matched patients undergoing uncemented total knee replacement. The control group were treated in the postoperative period with the leg positioned flat in extension (48 patients). The CPM group were placed on a CPM machine at 90° of knee flexion for twelve hours immediately post-operatively (46 patients). Haemoglobin and haematocrit levels, blood transfusion requirement, length of hospital stay, range of motion and complications were compared. In addition, we measured ankle and brachial pressures in a separate group of 39 patients with the limb in three different positions: flat with the knee in extension (ABPI 1), raised with the knee in extension (ABPI 2), and finally with the knee flexed to 90° (ABPI 3). Results: The CPM group demonstrated a smaller drop in haemoglobin level (2.5 vs 3.1, p=0.013) and a reduced blood transfusion requirement (3 patients vs 14 patients, p < 0.05) in the post-operative period when compared to the control group. There was no significant difference in haematocrit drop, discharge range of motion, complications or length of hospital stay between the two groups. ABPI measurements were calculated in the standard fashion, the mean ABPI in each limb position being 1.17 (ABPI 1), 0.87 (ABPI 2) and 0.83 (ABPI 3) respectively. Conclusions: Short-term use of a CPM machine in the post-operative period reduces blood loss and appears safe following uncemented total knee replacement. We found limb arterial pressure to be reduced to the greatest extent with the limb in a position of 90° flexion at the knee, which may account for the reduction in blood loss seen in the CPM group

Introduction and Aims: The purpose of the study was to determine whether the addition of screws improved the fixation of the tibial base plate when using an uncemented total knee replacement. Method: In June 1999 a prospective randomised double blind study on tibial base plate fixation was started at our institution after Ethics Committee approval. Patients were randomly allocated to either having or not having supplementary screws inserted through the base plate. To date, 138 arthroplasties have been performed and 119 are available for study. Of these, 56 have screws through the base plate and 63 do not. Assessment was of the position of the components of the prostheses, as well as the presence of any radiological lucent lines. Results: The study is ongoing, and updated results will be presented. After a minimum of 12 months follow-up, 27 patients have some radiolucent lines at the prosthesis-bone interface on the tibial component of the knee replacement. Fourteen occurred where screws had been used and 13 when screws had not. One tibial tray subsided into the tibia without failure of fixation. No screws had been used in this case. Statistically no difference could be demonstrated between the two groups. Conclusion: The early results of our study question the value of supplementing base plate fixation in uncemented total knee replacements, especially considering the additional cost of the screws and the potential detrimental consequences of the screws

Introduction: Stiffness following Total Knee Arthroplasty is a serious and debilitating complication. There are many different patient and surgical factors implicated in it cause. Previous studies have suggested that it will occur in approximately 1% of TKR patients. Arthrofibrosis is an uncommon but potentially debilitating cause in an otherwise well positioned implant. The cause of this abnormal scar formation is as yet unknown. The treatment of this condition remains difficult and controversial. Revision of the TKR has been suggested as the gold standard treatment as other operative strategies have had limited success. Our approach to this problem has been to conserve the prosthesis and try to release the scar tissue. Aim: The aim of this study is to assess the results of open arthrolysis in the treatment of established arthrofibrosis. Method: 1522 patients undergoing primary uncemented TKR have been prospectively followed up (2022 TKR’s) using the International Knee Society Scores. 13 patients underwent open Arthrolysis for stiffness post-op (Incidence 0.64%). The average age was 65 (range 50–78). 6 cases were simultaneous bilateral procedures (Incidence 1.2% of simultaneous bilateral procedures). The average time between TKR and arthrolysis was 14 months. Our average follow-op was 7.2 years (range 2 – 10 years). Results: The average ROM just prior to Arthrolysis was 58°. The average ROM six months after surgery had improved to 91° (p< 0.05). The average ROM at last follow-up was 95° (p< 0.05) with an average Knee Society score of 155 (pain 83, function 72). No patients have required revision of their components. Conclusions: We have found open arthrolysis a successful approach to post-op arthrofibrosis. Although a large procedure it has been well tolerated by our patients. They have had an improvement in range of movement by six months which has been maintained up to 10 years

Aims

The mean age of patients undergoing total knee arthroplasty (TKA) has reduced with time. Younger patients have increased expectations following TKA. Aseptic loosening of the tibial component is the most common cause of failure of TKA in the UK. Interest in cementless TKA has re-emerged due to its encouraging results in the younger patient population. We review a large series of tantalum trabecular metal cementless implants in patients who are at the highest risk of revision surgery.

A consecutive series of patients with a hydroxyapatite-coated uncemented total knee replacement (TKR) performed by a single surgeon between 1992 and 1995 was analysed. All patients were invited for clinical review and radiological assessment. Revision for aseptic loosening was the primary outcome. Assessment was based on the Knee Society clinical score (KSS) and an independent radiological analysis. Of 471 TKRs performed in 356 patients, 432 TKRs in 325 patients were followed for a mean of 16.4 years (15 to 18). The 39 TKRs in 31 patients lost to follow-up had a mean KSS of 176 (148 to 198) at a mean of ten years. There were revisions in 26 TKRs (5.5%), of which 11 (2.3%) were for aseptic loosening. Other further surgery was carried out on 49 TKRs (10.4%) including patellar resurfacing in 20, arthrolysis in 19, manipulation under anaesthetic in nine and extensor mechanism reconstruction in one.

Survivorship at up to 18 years without aseptic loosening was 96% (95% confidence interval 91.9 to 98.1), at which point the mean KSS was 176 (134 to 200). Of 110 knees that underwent radiological evaluation, osteolysis was observed in five (4.5%), one of which was revised.

These data indicate that uncemented hydroxyapatite-coated TKR can achieve favourable long-term survivorship, at least as good as that of cemented designs.

We report the clinical and radiographic outcome of a consecutive series of 219 hydroxyapatite-coated total knee replacements with a follow-up of 5 to 8 years.

Patients who fulfilled the entry criteria were included in a prospective study from early 1997 to late 1999. Regular clinical & functional assessment was subsequently performed using the Knee Society Score, WOMAC & SF-12 self-assessment questionnaires. Analysis of fluoroscopically controlled radiographs was performed using the American Knee Society Score.

All living patients (186 knees) were followed-up. Exhaustive efforts were made to ensure that no patient was lost to follow-up. 28 patients (30 knees) were deceased. There have been 3 revisions.

The mean pre-operative Knee Score of 43.8 increased to 77.1 and the mean pre-operative Function Score of 20.3 increased to 63.4 at 5 years. The WOMAC scores also showed marked improvement from pre-operative status after 5 years minimum follow-up: pain 250 pre-op to 157, stiffness 115 pre-op to 56 and function 910 pre-op to 588.

There was no radiographic evidence of loosening or migration. The average American Knee Society Score for each component was 4. Small gaps between the bone-implant interface were observed to heal over the first year. A separate phenomenon of focal osteopenia is also described in a small number of well-fixed femoral components (12 of 219).

To date, 3 prostheses have been revised, 2 due to deep infection and 1 due to tibial tray subsidence. A survivor-ship of 98.6% has been achieved at 8 years.

We believe this to be the first medium term study for the Duracon HA coated knee arthroplasty system, showing excellent clinical and radiographic outcome, with 100% follow-up at 5 to 8 years.

Aims: Cementless þxation in TKA remains controversial because of less predictable osseointegration and difþculty interpreting þxation interfaces. Methods: This study evaluated 567 consecutive primary LCS mobile-bearing TKA with in-depth RLZ analysis of all cases by one author (T.K.). Mean followup was 5.7 years (2.0-14.9), mean age 69 years (70% females). Diagnosis included 8.3% rheumatoids. The same porocoated femoral and patella components were utilized. Tibial components included a 3-þn (ACL/PCLretaining) or tapered-cone design (PCL-retaining/substituting). Bone treatment included generous use of autograft: cortico-cancellous struts for slope-off deformities and soft bone, morselized impaction for central zones, slurry to achieve interference þt. Results: Good/excellent results were 94.7%. Minimal femoral/patella lucencies; Tibial tapered cone (n = 523) had one (0.2%) failure. Lucencies of 1–2 mm (usually isolated) were noted in 2% medial, lateral, posterior and 4% anterior/central zones, all of which remained stable; 3) Tibial 3-þn tibial design (n = 44) had 3 failures (6.8%) with RLZ > 2mm in multiple zones. Conclusion: Cementless þxation with LCS poro-coat prosthesis was successful in all femoral/patellar and 99% of the tibial-cone design. The 3-þn design had multiple RLZ and a higher failure rate (not recommended).

Introduction. The ideal type of total knee arthroplasty (TKA) prosthesis remains a debatable topic with many different options available. Uncemented TKA has been a viable option due to its decreased operating room (OR) time but also because of its proposed improved long term fixation. Unfortunately, in the past uncemented TKA was associated with increased blood loss. Surgical technique and perioperative treatments have changed since these original studies and tranexamic acid (TXA) has become the gold standard for TKA blood loss management. The objective of this study was to evaluate if there was a difference in hemoglobin and hematocrit change, along with blood loss volume during surgery between cemented and cementless TKA when modern blood loss techniques are utilized. Methods. We retrospectively reviewed data from TKAs performed by three high volume surgeons between 2016 and 2019. We excluded bilateral TKA, revisions, hardware removal intraoperatively and other indications for TKA than primary OA. Power analysis determined 85 patients in both the cementless and cemented TKA groups. Patients were matched 1:1 for age, sex, BMI and surgeon. Use of TXA, intraoperative blood loss, differences in hemoglobin and hematocrit pre- and postoperatively days one, two, and three were recorded. Continuous variables were analyzed using T-tests and categorical variables were evaluated using Chi-squared tests. Results. No significant difference was observed between the cementless and cemented groups for hemoglobin (p=0.214), hematocrit (p=0.164), or intraoperative blood loss volume (p=0.343). A trend towards significantly shorter OR time was seen in the cementless group (p = 0.058). Conclusion. With modern TKA surgery, including the use of TXA, there is no difference in perioperative blood loss between cemented and cementless TKA. Unlike previous studies, the use of modern blood loss salvage techniques in conjunction with cementless TKA fixation, does not result in more blood loss during the perioperative period

Introduction. Cementless total knees were historically associated with early failure. These failures, likely associated with implant design, made cemented total knee arthroplasty (TKA) the “gold standard”. Manufacturers have introduced newer uncemented technologies that provide good initial stability and utilize a highly-porous substrates for bony in-growth. Outcome data on these implants has been limited. In addition, these implants typically have a price premium which makes them difficult to use in the setting of cost containment and in at risk 90-day bundles. Our purpose was to compare 90-day outcomes of a new uncemented implant with those of a comparable cemented implant from the same manufacturer. We hypothesized that the implants would have equivalent 90-day clinical and economic outcomes. Methods. Ninety-day clinical and economic outcomes for 252 patients with prospectively collected data from the Michigan Arthroplasty Registry Collaborative Quality Initiative (MARCQI) database were reviewed. Ninety-day outcomes were compared between uncemented knees and an age-matched group of cemented knees (Triathlon cemented vs uncemented Triathalon-tritanium, Stryker Orthopedics, Mahwah, NJ, USA). Both cruciate retaining and posterior stabilized designs were included. MARCQI data: demographics, co-morbidities, length of stay, complications, emergency department visits, discharge disposition, and readmissions were reviewed. Financial data provided by the hospital's finance department was used for economic comparisons. Fischer's test was done to assess categorical data and a student's t-test was used to compare numerical data. Results. Uncemented knees had shorter length of stay (1.58 vs. 1.87, p<0.0001), were more frequently discharged home (90.48% vs. 68.75%; p<0.0001) and used less home care or extended care facilities (6.35% vs. 19.14%, p<0.0001; 2.78% vs. 11.72%, p=0.0001). More uncemented knees had “no complications”. Moreover, there were no reoperations in uncemented knees, compared to 19 reoperations in cemented knees most being manipulations (14 vs. 0, p=0.0028). Uncemented knees scored better than age matched counterparts Knee Injury and Osteoarthritis Outcomes Score (63.69 vs. 47.10, n=85 and 43, p<0.0001), and Patient Reported Outcomes Measurement Information System T-physical and T-mental (44.12 vs. 39.45, n=95 and 59, p<0.0001; 51.84 vs 47.82, n=97 and 59, p=0.0018). Cemented cases were more expensive overall, the surgical costs were higher ($6806.43 vs. $5710.78 p<0.01) and the total hospital costs were higher ($8347.65 vs. $7016.11 p<0.01). The 90-day readmission and hospital outpatient costs were not significantly different between the designs. Conclusion. The use of a modern uncemented TKA implants has increased, but data on outcomes and the economic impact has been limited particularly in regard to 90-day at risk global periods. Our study suggests that patients receiving an new uncemented TKA have a shorter length of stay, higher rate of discharge to home, better patient reported outcome measures, fewer complications and fewer reoperations than an age-matched group of patients receiving a similar, cemented design during the 90-day global period. Importantly, the uncemented knees had $1,095 less surgical episode costs (p< 0.001) and a 90-day cost savings of over $1,300 (p< 0.001). Uncemented TKA, when utilizing modern technologies, is successful and economically viable for an at-risk bundle. The results of this study should alleviate fears increased cost, early failure, complications or poor outcomes with the use of a modern uncemented TKA

Introduction. A total knee arthroplasty (TKA) is the standard of care treatment for end-stage osteoarthritis (OA) of the knee. Over the last decade, we have observed a change in TKA patient population to include younger patients. This cohort tends to be more active and thus places more stress on the implanted prothesis. Bone cement has historically been used to establish fixation between the implant and host bone, resulting in two interfaces where loosening may occur. Uncemented fixation methods provide a promising alternative to cemented fixation. While vulnerable during the early post-operative period, cementless implants may be better suited to long-term stability in younger patient cohorts. It is currently unknown whether the surgical technique used to implant the cementless prostheses impacts the longevity of the implant. Two different surgical techniques are commonly used by surgeons and may result in different load distribution across the joint, which will affect bone ingrowth. The overall objective of the study is to assess implant migration and in vivo kinematics following cementless TKA. Methods. Thirty-nine patients undergoing a primary unilateral TKA as a result of OA were recruited prior to surgery and randomized to a surgical technique based on surgeon referral. In the gap balancing surgical technique (GB) soft tissues releases are made to restore neutral limb alignment followed by bone cuts (resection) to balance the joint space in flexion and extension. In the measured resection surgical technique (MR) bone cuts are first made based on anatomical landmarks and soft tissue releases are subsequently conducted with implant components in-situ. Patients returned 2 weeks, 6 weeks, 12 weeks, 24 weeks, and 52 weeks following surgery for radiographic evaluation. Kinematics were assessed 52 weeks post-operatively. Results. No significant difference was observed between groups in maximum total point motion (MTPM) at any time point during the first post-operative year. MTPM of both the tibial and femoral component did not significantly change between the six month and one year follow up visits for both the GB (6 mths=0.67 ±0.34mm, 1 yr=0.65 ±0.52, p=0.71) and MR (6 mths= 0.79 ±0.53mm, 1 yr= 0.82 ±0.43mm, p=0.56) cohorts. MTPM for both components over the follow up period is displayed in Figure 1. No significant difference was observed in contact location or pattern on the medial condyle during deep flexion (Figure 2A). A significant difference (p=0.01) was observed, however, between surgical techniques in the lateral contact location at full extension (Figure 2B). No significant difference was observed in the magnitude of AP excursion for both the medial and lateral condyles within and between groups. Conclusion. Surgical technique did not impact the MTPM of an uncemented TKA design during the first post-operative year. By the six month post-operative period tibial and femoral MTPM plateaus indicating that osseointegration between the host bone and implanted components has occurred. Kinematic evaluation indicates contact locations anterior to the midline of the sagittal plane, paradoxical anterior translation, and a lateral pivot point, regardless of surgical technique

Introduction. Uncemented highly porous titanium implants have been shown to promote osseointegration, and may result in a durable construct for total knee arthroplasty (TKA). Given the mixed results of uncemented TKA, it is important to evaluate the early stability for this product. The objective of the following study was to use radiostereometric analysis (RSA) to assess early fixation of a highly porous tibial baseplate and metal backed patella. Methods. Twenty-seven patients (mean age 64 years, 30% female) undergoing primary TKA consented to participate in this prospective cohort study. All patients received a highly porous tibial baseplate, a metal backed patella and tantalum RSA bone markers. Implant migration was assessed using model-based RSA at 1.5, 3, 6, 12 and 24 months post-operative. Patient reported outcome measures were captured using the same follow-up schedule, and compared to pre-operative measures. Results. There were no adverse events affecting implant fixation, and no revisions. Patient function significantly improved by 3 months post-operation (p < 0.001). The highest rate of tibia and patellar component migration occurred over the first six post-operative weeks, with minimal migration thereafter. Mean maximum total point motion (MTPM) at 24 months was 0.72 (SD 0.34) mm for the tibia, and 0.44 (SD 0.25) mm for the patella. Three tibia baseplates migrated more than 1 standard deviation greater than the mean at 24 months, and also had continuous migration (> 0.2mm of MTPM) in the second post-operative year. One patellar component showed a rapid rate of migration between 6 and 24 months, whereas all other patellar components appeared to stabilize. Conclusions. Osseointegration appears to occur on the highly porous implant surface of the tibia baseplate and metal backed patella, as evidenced by implant stability. Further follow-up is required to determine if clinical loosening will manifest in the continuously migrating implants

Introduction The efficacy of total knee replacement (TKR) surgery is well documented throughout the literature. Results from cemented and cementless series reveal similar long-term reliable results in terms of function and survival. Less, however, is known of the long-term results of uncemented TKR with the use of hydroxyapatite (HA). The purpose of this paper is to present the long-term results of a series of TKR using an uncemented, HA-coated, PCL retaining prosthesis. Method During the period from August 1992 to December 1994 all patients undergoing TKR surgery were prospectively recorded in a consecutive series. Results were recorded pre- and post-surgery at regular intervals (both clinically and radiographically). The combined clinical Knee Society Score was used to evaluate outcome with routine radiographic evaluation done at 10 years. Results 217 patients (126 female, 91 male) were included in the study with 322 knees in total (75 simultaneous bilateral, 23 staged bilateral and 126 unilateral). The mean age was 70 years (range 34–88 years) with a mean follow-up of 11 years (range 10–12 years). 47 (21.7%) patients were deceased at 10 years. The principle indication for surgery was osteoarthritis. There has been 1 revision (0.3%) for infection in this series to date. There have been 7 (2.2%) deep infections requiring surgical intervention and 4 (1.2%) supracondylar fractures. At 10 years, mean knee score was 174 with range of movement 0–111 degrees. 95.4% of the series has currently been successfully followed up. 9 patients were unable to be contacted and lost to follow up. With revision as an end point, the rate of survival for the prosthesis at 10 years is 99.4%. Assuming worst case scenario for patients lost to follow up, survivorship is 95.4%. Conclusion The survival of this prosthesis has shown to compare favourably to other published results. A low rate of revision and infection combined with excellent clinical and functional outcomes suggests the use of HA with an uncemented TKR produces reliable long-term results

Aims

This study aimed to investigate the optimal sagittal positioning of the uncemented femoral component in total knee arthroplasty to minimize the risk of aseptic loosening and periprosthetic fracture.

Aims

The use of high tibial osteotomy (HTO) to delay total knee arthroplasty (TKA) in young patients with osteoarthritis (OA) and constitutional deformity remains debated. The aim of this study was to compare the long-term outcomes of TKA after HTO compared to TKA without HTO, using the time from the index OA surgery as reference (HTO for the study group, TKA for the control group).

Aims

The aim of this study was to compare the migration of the femoral component, five years postoperatively, between patients with a highly cross-linked polyethylene (HXLPE) insert and those with a conventional polyethylene (PE) insert in an uncemented Triathlon fixed insert cruciate-retaining total knee arthroplasty (TKA). Secondary aims included clinical outcomes and patient-reported outcome measures (PROMs). We have previously reported the migration and outcome of the tibial components in these patients.

Introduction. The use of a mobile-bearing knee system is increasing in modern total knee arthroplasty (TKA). Mobile-bearing TKA improves kinematics and is reliable and capable of providing substantial benefit for patients. The aim of this study was to report independent long term results of uncemented low contact stress (LCS) mobile bearing total knee replacement. Methodology. We examined the outcome of 138 consecutive patients who underwent uncemented LCS total knee replacement between 1996 and 2000. Oxford knee score was noted. Results. 138 patients underwent LCS total knee replacement during this period. The mean age was 71(37-90) years. 34 patients died and 104 patients were included in the study. The mean follow up was 10 (8-12) years. There was a significant improvement in the postoperative knee scores (P<0.001). 2 knees were revised, one due to infection and due to the subsidence of the tibial tray. Conclusion. The study has demonstrated excellent long term survivorship of the uncemented LCS total knee replacement irrespective of the deformity and diagnosis

There is a report that higher failure rate in uncemented total knee replacement components due to loosening. However, uncemented fixation has been an attractive concept because of bone preservation and revision surgery, potential improved load transfer, and decreased surgical time. “Regenerex” is a porous titanium layer with excellent initial fixation, and the promise of providing favourable biological fixation. This is used with the Biomet Vanguard total knee replacement. 14 patients had undergone total knee replacement surgery comprising 11 men and three women with an average age of 63.07 years, and a body mass index of 30.33. Three of these patients required revision, because of tibial component loosening within 12 months of surgery. There were two men and one woman with an average age of 63.33 and BMI of 34.55. Clinically, patients developed pain and a gradual deformity as a result of a symmetrical collapse of the proximal tibial bony support surface. Histopathology on the removed specimens shows the development of fibre cartilaginous metaplasia with evidence of necrotic bone. This was similar in all patients. There was no foreign body giant cell reaction, and no evidence of infection. The appearance was suggested of osteonecrosis, occurring gradually. The incidence of frequency of this complication with this component in our experience is of concern, and the aim of this presentation is to determine whether this is a more widespread phenomenon

Aims

Thresholds of acceptable early migration of the components in total knee arthroplasty (TKA) have traditionally ignored the effects of patient and implant factors that may influence migration. The aim of this study was to determine which of these factors are associated with overall longitudinal migration of well-fixed tibial components following TKA.